1. Field of the Invention
This invention relates to apparatus and methods for removing drift gages, or plugs, which have become stuck in pipe or couplings the internal diameter of which is being measured by, the drift gage or plug.
2. Description of Related Prior Art
American Petroleum Institute (A.P.I.) specifications require that all oil country tubular casing, and couplings if attached to the casing, be gauge drifted with a unique drift gauge in order to insure uniform internal diameter oft he casing and couplings. When an internal protrusion, or piece of scale, or other interference with the movement of the drift gauge is encountered, the gauge becomes lodged in the casing or coupling. This sticking is a frequent occurrence and the accompanying difficulties of breaking the stuck gauge causes much down time and expense in the manufacture of casing and couplings.
The drift gauge normally is propelled into and out of a casing by a mechanical drive attached to a powered drift gauge rod on which the drift gauge is carried. The mechanical drive and associated powered drift gauge rod is purposely underdesigned (underpowered) to simulate the hand drifting or gauging which occurs in the field. Another factor which causes sticking of a drift gauge to occur is that the powered drifter mechanical drive must operate at line speed to accommodate a definite production rate, and it is this speed, along with the drift gauge inertia, which lodges the drift gauge in a defective casing or coupling.
U.S. Pat. No. 5,208,967 discloses apparatus for extracting tubes, such as condenser and heat exchanger tubes, from their mountings, and includes a cylindrical gripping collar which has an internal dimension slightly larger than a tube to be extracted. The gripping collar is tiltable and, when tilted, the edges of the collar grip the tube and, when a longitudinal force is exerted on the collar, it extracts the tube from its mounting.
U.S. Pat. Nos. 5,052,659 and 4,976,483 relate, respectively, to a stake puller and a stake driving tool. Each comprises an element with an aperture or slot the edges of which, in a tilted position, grips a stake to be pulled or driven.
U.S. Pat. Nos. 4,492,274, 4,434,969 and 4,000,879 each describes a rod or pipe puller or pusher having a hollow member the edges of which, in a tilted position of the member, grip a rod or pipe to be pulled or pushed through the ground.